A diode is an electronic component that restricts the direction of flow of electric current. More specifically, it allows electric current to flow in one direction, but blocks electric current flow in the opposite direction. Accordingly, a diode can be thought of as an electronic version of a mechanical check valve. Circuits that require current flow in only one direction typically include one or more diodes.
Schottky diodes are diodes that are formed from the contact between a metal and a semiconductor rather than from a p-n junction. They have a lower forward voltage drop than a standard p-n junction diode. Schottky diodes generally have much lower junction capacitance than p-n junction diodes. The lower junction capacitance contributes to their high switching speed and their suitability for high speed circuits and radio frequency (RF) devices such as mixers and detectors. In addition, Schottky diodes may be used in high voltage applications.
For use in high voltage applications, Schottky diode manufacturers seek to provide devices that have superior properties for reducing power loss. Parameters used by manufacturers to assess the performance of such diodes include forward current conduction and reverse voltage blocking characteristics. Devices that provide high forward current conduction and a high blocking voltage are ideal for high voltage, low loss applications. Challenges to the successful manufacture of such devices include intrinsic properties of the materials used to fabricate the devices and physical defects that may be present in those materials.
Silicon Carbide (SiC) has emerged as a promising material for high-voltage and low-loss power semiconductor devices because of its high critical electric field. Moreover, Schottky barrier diodes (SBDs) that use SiC are currently commercially available. However, these devices demonstrate poor performance in comparison with the ideal performance potential of SiC. More specifically, currently available SiC-SBDs do not fully realize the high performance (high-voltage, high current capacity, and low-loss) potential of SiC. In addition, currently available SiC-SBDs exhibit performance degrading defects in the SiC epilayer of high-voltage versions.